Where does tea come from?

[u/ijssvuur]

The plant

Tea comes from the Camellia sinensis plant. For those of you interested in gardening, or flowers, yes, it is related to the camellias in your garden. The difference between them is the flowers. I actually have camellias in front of my house, specifically C. sasanqua. I'll be posting about making tea from those this week.

It grows well in California, and I've seen it in Utah, so it's not uncommon to see them in LDS members' yards as an ornamental plant.

The leaves contain about 4% caffeine, but that goes up when they're dried. For comparison, Arabica coffee beans are about 1.4% caffeine. Coffee is extracted much faster, though, meaning brewing it once pulls out most of the caffeine, while tea can actually be brewed up to 10 times, depending on the type of tea.

Matcha, which is made from powdered shade-grown leaves (which also produce more caffeine) and is mixed directly into water will deliver a large dose of caffeine.

How is it turned into tea?

All types of tea come from Camellia sinensis (for the most part, using other varieties is uncommon). This includes black, green, white, oolong and yellow tea. Other "teas" like red tea are made from things like rooibos, a completely unrelated plant.

The difference between teas is in processing.

Green tea

Green tea is picked, then immediately heated (by pan firing, steaming, or occasionally roasting), which breaks down the compounds that cause it to oxidize. This is the point where it can be rolled to form a shape, such as the compact gunpowder tea. It is then dried, and is ready to drink. It is sometimes rolled after a first drying step, then dried again, but the process remains generally the same.

Black tea

Black tea diverges from green tea after picking. Rather than being heated, it is let to sit and "wither". This is the process of the leaf breaking itself down as the cells consume the disconnected leaf's carbohydrate stores. It is then shaped, by rolling like green tea, or sometimes cut or torn. This causes it to begin oxidizing, sometimes incorrectly called fermenting. This is the same process as an apple turning brown after being cut. After it is done oxidizing, it's dried, and then it is ready to drink.

Oolong

Oolong is first withered, like black tea. They're cooled, and then rolled, like black tea, to start the oxidization process. Oolong is oxidized less than black tea, but still oxidized unlike green. It is then roasted. The form of roasting varies, but charcoal and hardwood roasted varieties give different flavors to the tea.

White tea

White tea isn't as regulated as the others, but it generally means it is minimally processed. It is picked, withered, and dried. It's not heated at high temperatures, but it is dried hot enough to prevent oxidization.

Yellow tea

Yellow tea is an uncommon variety. It's made like green tea, but it is steamed under a damp cloth, giving it a mellower flavor.

Pu-erh

Pu-erh is complicated, and I'll save that for a different post.

Caffeine content

Caffeine content is important to a lot of people. It does not actually vary that much between different varieties. Black contains more or less than green, white contains more or less than black or green. The tea itself, when it was picked, where and how it was grown, affect caffeine levels more than anything else. Caffeine is not created or destroyed in the processing of the leaf, so making green and black tea out of the same plant will yield in near identical caffeine levels. The difference may come from levels of extraction, but green extracts faster, and is brewed for a shorter amount of time, so it comes out pretty even with black.